Semiconductor modules comprise one or more semiconductor chips, which each comprise one or more semiconductors like diodes, transistors, thyristors and the like. In such modules, high power semiconductor switches like IGBTs are used for switching currents of more than 10 A and/or more than 1000 V.
As a rule, switching losses should be kept at a minimum, which may be achieved by fast switching. On the other hand, fast switching may also cause electromagnetic interference problems. The switching speed is therefore often controlled via a gate resistor or via intelligent gate drives controlling the gate current IC (for example by using IC or dlc/dt feedback). However, gate resistors usually do not help in case of short circuits and intelligent gate drivers may be expensive and complex to implement and control.
In most IGBT modules, the common emitter impedance is carefully designed to be identical for all IGBTs (in case of paralleled IGBTs) and not too large or too small. Usually, the actual value is chosen by the module manufacturer and cannot be changed by the module user.
Some IGBT modules provide an auxiliary emitter terminal, which may be used for providing the voltage for the gate drive. In particular, high current IGBT modules usually need an auxiliary emitter. Otherwise switching would be too slow. The PCB design cannot compensate the coupling.
Other types of modules do not provide auxiliary emitter terminals at all, thus leaving the responsibility to the PCB and gate drive designer. As a rule, short circuit protection for modules with low dl/dt damping has to be applied with external circuits, typically adding extra losses and extra components.
In this technical field, generic semiconductor modules are know from US 2013/153958 A1 and DE 100 05 754 A1.